It depends on your taste. If you're a fan of Harley Quinn and enjoy solo character-driven stories, then it's likely worth it. The comic might offer unique perspectives and adventures.
Bucky Barnes is indeed bisexual in specific comic iterations. It's a modern take that brings a fresh perspective to his character and reflects the growing acceptance and inclusion in the comic world.
Barnes and Noble often stocks manga, but it's best to check their website or call your local store to see exactly what's in stock. They might have a dedicated section for manga with a decent range of genres and titles.
Bucky Barnes is not gay in the comics. The comic narrative mainly explores his adventures and interactions with other characters without emphasizing his sexual preference.